Explanation:
Today, the solstice
is at 17:11 Universal Time, the Sun reaching the
southernmost declination in its yearly journey through planet Earth's
sky.
The December
solstice marks the astronomical beginning of winter in the
northern hemisphere and summer in the south.
To celebrate, explore this creative visualization of the Sun from
visible to extreme ultraviolet wavelengths, using image data from the
orbiting Solar Dynamics Observatory
(SDO).
Against a base image made at a
visible wavelengths,
the wedge-shaped segments show the solar disk at
increasingly shorter ultraviolet and extreme ultraviolet wavelengths.
Shown in false-colour and rotating in a clockwise direction,
the filters decrease in wavelength from
170 nanometres
(in pink) through 9.4 nanometres (green).
At shorter wavelengths, the altitude and temperature of
the regions revealed in the solar atmosphere tend to increase.
Bright at visible wavelengths, the solar photosphere looks darker in
the ultraviolet, but sunspots glow
and bright plasma
traces looping magnetic fields.
Watch the filters sweep around the solar disk in
this
animation of SDO's multiwavelength view of the Sun.